It is known to grind electrodes. This is commonly effected manually with open grinding—or separating wheels. Such methods are imprecise and dangerous. Furthermore, there are devices with open grinding wheels where the welding electrodes are guided through a guiding sleeve with a certain angle relative to the grinding wheel. Such devices are also expensive. In particular, it is expensive to adapt such a device to various types of welding electrodes or for different tips or cutting shapes. In particular, this requires a time-consuming exchange of the guiding sleeves.
A device where electrodes can be produced with a plurality (for example 6) of different electrode diameters with a plurality of different tip angles (for example 4) with many lengths is a valuable, cost-saving aid.
DE 100 10 520 A1 discloses a device for grinding welding electrodes with a grinding wheel. The grinding wheel rotates in a grinding wheel housing. The device is provided with an additional housing portion which is adapted to be fixed to the grinding wheel housing and which is provided with at least one opening for guiding a welding electrode for grinding in a defined position relative to the grinding wheel. The plane of the grinding wheel is essentially the separating plane between the grinding wheel housing and the additional housing portion. The additional housing portion can be provided with a plurality of adjacent, different openings for receiving different kinds of welding electrodes. The additional housing portion can, however, also be provided with a plurality of adjacent openings having an axis cutting the plane of the grinding wheel under different angles. A radial slit can be formed in the grinding wheel housing extending along the front end of the housing, which is used to pass a welding electrode for cutting at the outer perimeter of the grinding wheel. The grinding wheel of the disclosed device is fixed to a grinding wheel reception which in turn is connected to a driving shaft of a driving motor. The entire device forms a portable unit.
US 2004/0127149 A1 discloses an assembly where two parallel grinding wheels with different grain sizes are used. A first grinding wheel rotates in a space between the motor unit and a first housing portion. The second grinding wheel rotates in a second space between the first housing portion and the second housing portion. The housing portions are provided with openings for guiding the welding electrodes. The known assembly enables the use of different grinding wheels with standard diameters without the need of an exchange.
Further to a motor in a motor unit the assembly makes use of further housing portions: a motor flange directly screwed to the motor unit and at least one housing portion provided with openings for guiding the electrodes. The openings extend from the side of the housing portion opposite to the motor in the direction of the grinding wheel rotating between the motor flange and the housing portion. Depending on the amount of grinding wheels further housing portions are added. Here also the openings extend from the side opposite the motor. In other words, the electrodes are always inserted into the openings in a direction towards the motor. Depending on the amount of housing portions the assembly is relatively long and requires a long driving shaft. Several fixing elements, such as screws, nuts, pins, etc. are required for fixing the housing portions.
US 2008/0108284 A1 discloses an assembly where two grinding wheels or grinding surfaces having a different grain size rotate in practically one plane in a common space. The grinding surfaces of the known assembly are facing opposite directions. A third wheel with a larger diameter is arranged between such grinding wheels. Such wheel is used for cutting electrodes. The assembly either operates with one grinding wheel with two grinding surfaces having different grain sizes or with a grinding wheel assembly comprising at least two grinding wheels.
The bore holes for guiding electrodes are produced with high precision regarding the angle. It is understood that the corresponding grinding wheel rotates in a defined position relative to the housing. With different thicknesses or with the use of several grinding wheels this is not ensured anymore. In such a case the grinding angle is not the target value.
During the production of simple grinding wheels the unprocessed raw disc is dipped into a bath for application of the grinding means. Accordingly, it is difficult to produce grinding wheels with a different grain size on the top side and bottom side. It is, therefore, much simpler to use a grinding wheel assembly with two grinding surfaces on different grinding wheels. In order to ensure that the grinding surface still rotates in the plane required for the high precision of the grinding angle very thin grinding wheels are used. The grinding wheels have a thickness which is selected in such a way that all grinding wheels together have the thickness of a standard grinding wheel which is used for simple assemblies. Consequently, the assembly only operates with high precision if grinding wheels are used which are individually manufactured.